I inform you that today I started testing of the S/MIME encryption and signature verification plugin for Roundcube. Encryption and signing, as I hope, will be implemented before the end of the year.
I need a wide variety of sample letters for testing. So I'll be very grateful if someone sends me a letter. My certificate for encryption is given below. The signed letter should contain the sender's certificate is attached.
If you are interested in my work, I'll be happy to answer questions.
Vladimir Gorpenko,
Moscow
-----BEGIN CERTIFICATE-----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HtdIvU+OBsy50t5cIsDUXN4VqL5S5dz1uHwKjfbYW+YO0CgEGLFJXkFroS3vgKPu
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KpHGRu2OKI1RkhTOD8SehUqBFAmovaUpto/erX+2sfEjmQAGIeA83FHJS7lh1y6z
dr0aLo29esTSiWAb+uxry7cQYI/hhvrClOd/ajO8SNiYt51tPZLWiYFN0aYE03jb
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b9bxBabWd3sNJgqkJ5LtQ0DF1rKoiH90zVh/lO9U11Lru/vQq1y+wEajS2iE3rh2
v/S0mjNbTT7icEU22FyGjMRB6iCbq/X7OuL/K4IsauN+8xYdUJ2jyiPuzNUb/5sF
SGphx4fbpMjSu8u/ylPN5E4JrvxR1/tnzEQskIPCCergzSIUQFWPLtXAg6ZhQczz
TeJEcyZO4h54S/AMHrRO+H8LgUL4b2SeQx9d
-----END CERTIFICATE-----